I can't get this to work. I get the error:
[PARSE_SYNTAX_ERROR] Syntax error at or near 'SHOW'.line 2, pos 0

insert into my_target_table (database, tablename, istemporary, information)
SHOW TABLE EXTENDED LIKE 'mytable';

I would not have expected that to work as it violates rules I know about SQL and the purpose of the semicolon. And it does not work.

[PARSE_SYNTAX_ERROR] Syntax error at or near end of input.line 1, pos 75

Use  DESCRIBE EXTENDED customer AS JSON 
this returns as a json data  . This you can load 

Applicable to databricks 16.2 and above

https://docs.databricks.com/aws/en/sql/language-manual/sql-ref-syntax-aux-describe-table